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Table 1 Comparison of subjects who were included to those who were excluded due to missing data

From: Asthma incidence and risk factors in a national longitudinal sample of adolescent Canadians: a prospective cohort study

 

Included

Excluded

p-value*

(n = 2,038,890)

(n = 443,720)

%

%

Sex

   

   Male

50.0

53.3

 

   Female

50.0

46.7

0.51

Age group

   

   12-13

27.3

31.9

 

   14-15

28.3

36.3

 

   16-18

44.4

31.8†

0.03

Area of residence

   

   Urban

80.9

81.0

 

   Rural

19.1

19.0

0.97

BMI

   

   Normal

80.0

64.5

 

   Overweight or obese

20.0

35.5*

<0.001

Passive smoking exposure

   

   Absent

59.5

63.5

 

   Present

40.5

36.6

0.44

Personal smoking

   

   Never/Former

83.1

87.1

 

   Occasionally/Daily

16.9

12.9

0.29

Physical exercise

   

   Inactive

85.6

  

   Active

14.4†

  

Income

   

   High

15.7

16.1

 

   Middle

66.8

58.4

 

   Low

17.4

25.5

0.27

  1. *Comparing those who were included to those who were excluded.
  2. †No information was presented for the excluded population due to low cell counts.
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BMC Pulmonary Medicine

ISSN: 1471-2466

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